The forecast is for a cloudless sky this morning, boundlessly high and cobalt blue — just as it was exactly 11 years ago, when a pair of pirated airliners hurtled into the Twin Towers and killed 2,753 innocents.

The Pentagon was struck that day, too, while a fourth plane, bound for Washington, was brought down in a Pennsylvania meadow — but there was never any doubt that New York City was at the top of Islamist terror’s target list.

Just as it is today.

Given the city’s reputation as a symbol of Western culture and commerce (and home to a large Jewish population), it was certain terrorists would seek to strike here again after 9/11.

And they tried. But not once, in numerous separate efforts, were they successful.

Their failures weren’t simply bad luck: After 9/11, Police Commissioner Ray Kelly set up a crack counter-terror operation that’s proven critical to keeping the city safe from Islamists.

New York’s Finest, which lost 23 of their ranks on 9/11, have managed to keep terror at bay, even as small-minded critics — from the New York Civil Liberties Union to the Associated Press and The New York Times — sought to hamstring them.

The FDNY — which suffered 393 fatalities, the largest number of any response agency in US history — has also faced pushback: Federal Judge Nick Garaufis has all but named himself fire commissioner, dictating rules for the department and, most troubling, blocking its ability to hire.

As a result, the city hasn’t been able to take on any new firefighters in years. The potential consequences, in the event of another attack, seem obvious.

Today at Ground Zero, family members will read the names of those who died there on 9/11.

Bagpipes will play.

Silences will be observed.

But behind the scenes, rest assured, the city’s cops and firefighters will be carrying on their vital work.

A new police unit, the World Trade Center Command, with more than 200 officers, will be on patrol.

And, of course, America’s men and women in uniform will be fighting the War on Terror overseas. (Reports yesterday said the No. 2 leader of Al Qaeda in the Arabian Peninsula, Said al-Shihri, was killed in what was likely a US drone strike.)

Eleven years after the worst foreign attack on continental US soil, New York has remained safe.

Say a prayer of thanks for the cops, firefighters and troops who’ve kept it so.